A prototype wireless sensor network system for a comparative evaluation of differential and absolute barometric altimetry

Ethernet and PC‐based experiments on barometric altimetry using MEMS in a wireless sensor network

“…For instance, changes in the atmospheric pressure cause a deflection to the sensing membrane of a capacitive pressure sensor (CPS), which forms a parallel plate capacitor along with the silicon die and the vacuum cavity formatted in-between. Thus, research that is in line with laboratory experimentation on MEMS barometric pressure sensors [8,9]. Such sensors are nowadays accommodated in several high-end application systems (e.g., in consumer electronics, avionics, navigation, and positioning systems, etc.)…”

“…The first experiment applies to differential barometric altimetry ; that is, altitude measurements are obtained from the two separated endpoint devices (hereafter, referred to as altimeters ) and thereafter, the in‐between absolute height difference is estimated. Because ambient air pressure decreases at a standard rate as elevation increases , absolute height determination in‐between altimeters can be obtained from either the hypsometric equation given in (1) or the international barometric formula [9,31] given in (2). The former equation requires an additional measurement of the air temperature, which is considered to be of constant value in‐between altimeters; thereby illustrating an isothermal atmosphere .…”

“…Experimental setup of the proposed example is presented in Figure . Because identical pressure sensors feature a deviation to the output signal when acquiring data at the same height , a reference measurement is needed for the determination of this value. Therefore, altimeters should initially be placed at the same height ( h = 0) and obtain a set of measurements.…”

“…The proposed example attempts to provide students with a practicable examination of these two methods for the absolute height determination. While differential barometric altimetry is of significantly increased accuracy, it features the unwanted deviation of sensors output which cannot be defined by one‐time calibration . On the other hand, absolute barometric altimetry is not reliable for outdoor measurements due to the increased variations of atmospheric pressure .…”

“…Considering current trends and future directions in MEMS market , the authors of this study have recently carried out a research that is in line with laboratory experimentation on MEMS barometric pressure sensors [8,9]. Such sensors are nowadays accommodated in several high‐end application systems (e.g., in consumer electronics, avionics, navigation, and positioning systems, etc.)…”